By: Patricia Gannon, Esq. and Marcela Bermudez, Esq.
Effective October 14, 2025, U.S. Customs Border Protection (CBP) systems will only accept “M” (Male) or “F” (Female) in the sex field of Advance Passenger Information Systems (APIS) transmissions. Any other characters will result in an “X Response-Insufficient Information” error, requiring airlines to resubmit the passenger data with corrected information.
As background, in July, CBP instructed airlines and other travel carriers on a new rule that they must submit “M” (male) or “F” (female) in the sex field of the pre-departure information they transmit to CBP through the APIS, even if the traveler’s passport contains a sex indicator other than M or F or does not otherwise indicate the sex of the traveler.
This new rule, and others, is based on Executive Order 14168, Defending Women from Gender Ideology Extremism and Restoring Biological Truth to the Federal Government.
Identifying only binary sex recognition changes the previous practice of airlines being able to list gender markers other than just “M” (male) or “F” (female)—including an “X” gender marker to CBP before a flight. Should a passenger’s passport list a gender other than M or F, the carrier will have its own way of deciding which gender to use.
Airlines remain responsible for comparing the travel documents passengers present with the information transmitted to CBP. Airline carriers must ensure accuracy in all APIS data submissions, including traveler sex designation and passport number formatting. Traveling with a gender marker that does not match your physical presentation can lead to confusion or increased scrutiny from security personnel. You may be subject to delays and questions if there is a discrepancy. Some countries are issuing warning, like Canada who allows for X gender passports. They acknowledge that other countries may not accept this designation.
